1. Field of the Invention
This invention is directed to a stamping die for use in a punch press. The stamping die has a programmable logic microcontroller secured to the die body to receive and process signals from various sensing devices located on the die to sense die malfunctions when the punch press is in operation.
2. Description of the Prior Art
Metal stamping dies that are utilized in punch presses are commonly equipped with sensing devices such as switches, pressure sensitive devices and proximity devices. These sensing devices are used to detect malfunctions in the operation of the die as the punch press operates. Some typical malfunctions are strip misfed or misplacement, doubling of material thickness due to slugs being pulled on the punch, folding of the strip due to obstructions to the feed movement, part ejection failure, misposition of die components and other die failures which can occur as the punch press operates. The use of sensing devices on the die itself is well known.
It is also well known to use programmable logic controllers to monitor the state of the sensors and their relationship to the movement of this punch press and/or the strip of material being punched. The components of the die can also be monitored by the programmable logic controller for position and for integrity of the die. The stamped part can be monitored for desired features on the part. Forming forces can also be monitored.
Programmable logic controllers are commonly known, commercially available devices. For use on a punch press, they require additional packaging or housing in an enclosure to provide protection from fluids, dirt, and also require isolation from vibration. The isolation from vibration is usually accomplished by physically displacing the programmable logic controller away from the stamping press which is the source of vibration. Such positioning requires a connection from each sensor in the die to the programmable logic controller, resulting in a great number of wires that are vulnerable to damage and misconnection. An intermediate connection or junction box is sometimes utilized to alleviate long runs of individual wire connectors, but such an arrangement adds expense to the system.
I have found that a programmable logic microcontroller that is greatly reduced in size from the typical programmable logic controller can be mounted directly onto the die body of the stamping die. The components of the programmable logic microcontroller are encapsulated in an epoxy resin or other material or are enclosed in a hermetically sealed casing to keep fluid, dirt and vibration or other detrimental environmental factors from reaching the programmable logic microcontroller. With the programmable logic microcontroller fixed directly to the die body, wiring from the individual sensors to the programmable logic microcontroller is contained within the die itself and terminated at the die mounted microcontroller.
An annunciator panel including light emitting diodes and nomenclature describing the malfunctions sensed by each of the sensing devices is contained on the exterior face of the programmable logic microcontroller. When a sensing device indicates a malfunction of the die, a signal is sent to the programmable logic microcontroller on the die itself and that signal is transmitted to a power block within the punch press control enclosure. That signal then causes the punch press to stop.